/****************************************************************
 *
 * The author of this software is David M. Gay.
 *
 * Copyright (c) 1991, 1996 by Lucent Technologies.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose without fee is hereby granted, provided that this entire notice
 * is included in all copies of any software which is or includes a copy
 * or modification of this software and in all copies of the supporting
 * documentation for such software.
 *
 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY
 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 *
 ***************************************************************/

/* g_fmt(buf,x) stores the closest decimal approximation to x in buf;
 * it suffices to declare buf
 *      char buf[32];
 */

#ifdef __cplusplus
extern "C" {
#endif
 extern char *dtoa(double, int, int, int *, int *, char **);
 extern char *g_fmt(char *, double, int, int);
 extern void freedtoa(char*);
#ifdef __cplusplus
        }
#endif

 char *
g_fmt(register char *b, double x, int mode, int ndigits)
{
        register int i, k;
        register char *s;
        int decpt, j, sign;
        char *b0, *s0, *se;

        b0 = b;
#ifdef IGNORE_ZERO_SIGN
        if (!x) {
                *b++ = '0';
                *b = 0;
                goto done;
                }
#endif
        s = s0 = dtoa(x, mode, ndigits, &decpt, &sign, &se);
        if (sign)
                *b++ = '-';
        if (decpt == 9999) /* Infinity or Nan */ {
                while(*b++ = *s++);
                goto done0;
                }
        if (decpt <= -4 || decpt > se - s + 5) {
                *b++ = *s++;
                if (*s) {
                        *b++ = '.';
                        while(*b = *s++)
                                b++;
                        }
                *b++ = 'e';
                /* sprintf(b, "%+.2d", decpt - 1); */
                if (--decpt < 0) {
                        *b++ = '-';
                        decpt = -decpt;
                        }
                else
                        *b++ = '+';
                for(j = 2, k = 10; 10*k <= decpt; j++, k *= 10);
                for(;;) {
                        i = decpt / k;
                        *b++ = i + '0';
                        if (--j <= 0)
                                break;
                        decpt -= i*k;
                        decpt *= 10;
                        }
                *b = 0;
                }
        else if (decpt <= 0) {
                *b++ = '.';
                for(; decpt < 0; decpt++)
                        *b++ = '0';
                while(*b++ = *s++);
                }
        else {
                while(*b = *s++) {
                        b++;
                        if (--decpt == 0 && *s)
                                *b++ = '.';
                        }
                for(; decpt > 0; decpt--)
                        *b++ = '0';
                *b = 0;
                }
 done0:
        freedtoa(s0);
#ifdef IGNORE_ZERO_SIGN
 done:
#endif
        return b0;
        }

